Cloning genes that resist disease.

• Position: Plant genetic engineering

Scientists from Purdue and Cornell universities for the first time have used a new method of gene isolation to clone a disease-resistance gene from a crop plant. The breakthrough has several significant aspects:

* It is the first time a disease-resistance gene has been cloned and moved from one crop variety to another. The research opens the door for improved disease resistance in a variety of crops.

* The findings could decrease the need for pesticides by the turn of the century.

* The path to discovery gave unexpected insights into the biology of how plants fight diseases.

* It represents the first time a gene in a crop plant has been isolated using "map-based cloning," a technique initially employed in the human genome project (the effort to map all human genes).

"Unlike other methods of creating disease-resistant plants, where a bacterial gene is moved into plants, here we have taken a gene from a disease-resistant tomato plant and moved it into a susceptible tomato plant," explains Greg Martin, assistant professor of agronomy at Purdue and lead investigator on the three-year project. "The benefit to the general public is that disease-resistance genes already existing in plants offer the best forms of pest control for agriculture. This inherent disease resistance means fewer pesticides will be...